The long term goal of this project is to maintain a cell culture of the inner ear, the auditory nerve, and the auditory nuclei of the brain stem. These structures represent the first echelon of the auditory nervous system and such a model would mark a significant contribution to studies on the auditory system. The myriad physiologic and pharmacologic manipulations which could be performed on such an in vitro system could rapidly expand our knowledge of the auditory system. Using aseptic techniques of surgery and cell culture the inner ear membranous tissue, the eight nerve fibers, and the auditory nuclei of the brain stem will be harvested from three animal groups--chicken embryos, neonatal gerbils, and neonatal mice.These tissues will be explanted onto cover slips pretreated with collagen and will be incubated with culture media.The living tissue will be examined during maintenance with phase--contrast microscopy. Tissue treated with fixatives will also be examined with fluorescent markers of nerve fibers. The morphology of the cultured tissue will be evaluated. Electrophysiologic recordings from the cultured tissue will be obtained. With the thin monolayer configuration of the cultured tissue, it will be possible to clearly identify the cells from which electrical signals are recorded. This is a unique opportunity to examine multiple sites along the auditory pathway in a continuous manner.